The present invention relates generally to high altitude vehicles and is particularly concerned with a high altitude airship launch and retrieval system.
Currently, vehicles such as satellites, space shuttles, and the like must be launched to high altitudes by rockets. This requires enormous expenditure of fuel, and, absent very high geosynchronous orbit, do not maintain position relative to the earth. Thus, deployment of conventional satellites carrying communication devices or signaling systems is a very expensive proposition. If the equipment on the satellite should malfunction, retrieval and maintenance is often not cost-effective and may even be impossible.
It is known to use airships or dirigibles for low altitude applications, such as surveillance, signaling, collecting and transmitting meteorological data, and the like. These are typically permanently tethered to a fixed ground location and are deployed in the lower atmosphere. Such airships are described, for example, in U.S. Pat. No. 5,470,032 of Williams, Jr. et al., U.S. Pat. No. 4,120,259 of Wilson, U.S. Pat. No. 4,842,219 of Jakubowski et al., and U.S. Pat. No. 2,151,336 of
U.S. Pat. No. 3,174,705 of Schiff describes deployment of a balloon-like vessel as a space station at a high altitude. The balloon is launched by filling it with helium or the like, and its lateral position is maintained for the first mile of ascent by means of a cable. The cable is then dropped, and the balloon continues to rise to an altitude of 65,000 feet. Although this is less expensive than a rocket launch system, it is subject to problems in accurate station-keeping during the remainder of its rise to the desired altitude, and there is no reliable means for recovery and maintenance.